Recently Wizards is starting to remind me of the last days of TSR. Inconsistent product quality, a seeming ignorance of what products the customers actually want made worse by a general oversaturation of products, and a steady loss of business to competing that they don't really understand (Magic: The Gathering in the case of TSR, Hearthstone and its imitators in the case of Wizards).

Stop giving them a hard time. They've only had 25 years to figure out how to distribute things.
On a slightly more serious note though I'm seeing a lot of theories that Jace is printed at his own rarity, and that's why he wasn't repeated even though all the other rares and mythic rares were.

Now that I look into the design document, lots of individual things look good but many choices seem to go against the general theme of streamlining the game and making it conssitent that Wizards has adopted in the last decade or so. In particular:
The legendary supertype is applied to sorceries, but in a manner completely different (though not entirely disconnected) from its other uses.
Adding rules baggage to the subtype "saga" completely reverses their decision on legends and walls.
The "historic" word seems kind of random. In particular, why are random artifacts always included? Though since this is almost certainly a block only mechanic it's not the biggest deal.
The use of "any target" is a good way to open up design space on burn spells, but can be confusing on other cards. In particular, if I'm reading this right, "destroy any target" wouldn't be able to target lands, artifacts or enchantments (unless they also happened to be creatures). If they just don't use this terminology on things which are not burn spells I suppose it's fine.
That being said, this move is not necessarily a bad thing. It could lead to a game with more flavor and more room for creative usage of the rules, rather than the somewhat staler game that Magic has more recently become. In particular if they make good use of reminder text it should be fine.